Hermetically-sealed containers can be readily produced by the so-called blow/fill/seal techniques. Utilizing such techniques, a container body is first blow molded from an extruded parison segment, then charged (or filled) with desired liquid or solid contents, and thereafter immediately sealed by a preformed insert while additionally molding the parison segment at the container neck and throat region about the inserted, preformed closure subassembly. See, for example, the container structure disclosed in U.S. Pat. No. 4,596,110 to Weiler.
The hermetically sealed container structures that result from such a blow, fill and seal container molding procedure, especially those with a removable overcap as shown in the aforementioned patent, are very useful and have come into widespread usage. However, under certain conditions of relatively extreme usage, the preformed, inserted closure can become disengaged or loosened from its engagement with the material forming the container throat region. Such disengagement not only raises the risk of environmental contamination of the container contents, but also can cause dispensing problems when the container contents is about to be used after the container has been opened by twisting off the overcap that protects the insert. Examples of such extreme usage conditions include excessive torque applied to the inserted closure or an excessive force applied in a direction away from the container longitudinal axis.
A practical means for overcoming this loosening problem is needed and has been diligently sought, but has not been easy to achieve. However, the present invention provides a practical solution to this problem and permits the utilization of a wide variety of pre-molded inserts in conjunction with hermetically sealed, molded containers.